Three position valve

ABSTRACT

A valve wherein an inlet is connected to either of two outlets alternatively, or to neither of the outlets, in accordance with the relationship between a pilot pressure and an operational pressure.

United States Patent [151 3,683,966 Payne 1451 Aug. 15, 1972 [54] THREE POSITION VALVE 3,349,800 10/1967 Herion et al l37/625.48 X 2,628,608 2/1953 Loecy ..92/52 X [72] Invent Payne 2,745,429 5/1956 Crookston ....251/31 x 3,057,163 10/1962 Alping ..92/52 [73] Assignee: Offshore Systems Inc., Houston, 3,152,520 10/ 1964 Heese ..92/52' Tex. 2,560,841 7/ 1951 Bishop ..l37/625.4.8 [22] Filed: April 2, 1970 FOREIGN PATENTS OR APPLICATIONS [21] App1.N0.: 25,104 1,110,970 7/1961 Germany ..251/3l 565,012 11/1932 Germany ..,137/625.48

Primal), Examiner samuel Scott V 581 Field of Search ...l37/625.48; 251 31, 177, 17s, gggj'gggg gg fi ggfi Rben 251/186; 92/6, 52 v [56] R 1 C'ted I I [57] ABSTRACT e erellces I A valve wherein an inlet is connected to either of two UNITED STATES PATENTS outlets'altematively, or to neither of the outlets, in ac- I cordance with the relationship between a pilot pres- 3,302,535 2/1967 Procter et a1. ..92/52 1 3,020,927 2/1962 McLaughlin l37/625.48 x sure and pressure- 1,314,559 9/1919 Wilson ..251/178 X 9 Clains, 3 Drawing Figures Paten ted Aug. 15, 1972 2 Sheets-Sheet 1 Patented Aug. 15, 1972 2 Sheets-Sheet 2 ,4 rramvfr THREE POSITION VALVE BACKGROUND The valve which forms the basis of the subject invention has general application to offshore oilwell operation. However, the subject valve has other applications as well. The subject valve was developed for use in the offshore area especially due to the hostile environment and the hazardous operating conditions. More specifically, due to the hazardous nature of petroleum production in general and offshore production in particular, many drilling contractors specify that redundant type controls for blowout preventers and the like be supplied in the drilling equipment. In the past, the redundant controls at the subsurface location have required extensive duplication of expensive and critical equipment. The subject valve eliminates some of the duplication of parts without any reduction in safety.

The subject valve permits a BOP or the like to be controlled by two separate control systems at the surface. The control is effected such that any malfunction in either of the control systems can be eliminated and the malfunctioning part of the control system brought to the surface for repair without interrupting operation of the production equipment.

SUMMARY OF THE INVENTION The valve which forms the subject of this invention includes a sliding piston which selectively interconnects a single inlet with either one of two outlets alternatively or with neither of the outlets. Thus, the inlet can be effectively blocked from communicating with either one or both of the outlets.

The valve selectively interrupts or controls fluid flow in the hydraulic control line in which it is inserted. The piston is positioned as a function of the relationship between an operational pressure which is applied by one source and a pilot pressure or reference pressure which is applied by another source. The relative pressures and the configuration of the piston selectively control the location and operation of the pistonrelative to the inlet and outlet ports.

The outlet ports are so arranged that when the piston is in the blocked condition, neither of the outlet ports communicate with the inlet portor the other outlet port.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram of a system wherein the instant valve is utilized;

FIG. 2 is a cross-sectional side view of the valve which forms the instant invention; and

FIG. 3 is a cross-sectional end view of the valve shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a schematic block diagram of a system wherein the subject valve is utilized. Typically, the system may be a hydraulic system wherein hydraulic fluid flows in the lines and is utilized to transmit pressure signals in the system.

Typically, the system may be utilized in a subsea oilwell drilling operation. The system may be utilized to control a blowout preventer (BOP) or the like.

Blowout preventer 10 is schematically represented. A suitable piston 10A in the schematic BOP is connected to suitable BOP rams or the like. Depending upon the actuation of BOP 10, the BOP rams may be operated wherein the oilwell which is being drilled may be effectively closed to prevent an undesirable blowout of the well. Piston 10A of BOP l0 effectively divides BOP 10 into separate chambers. The chambers are selectively supplied with hydraulic fluid, under pressure, to act upon piston 10A and cause motion thereof.

7 One chamber of BOP 10 is connected via a hydraulic line to the outlet port of shuttle valve 11. The other chamber of BOP 10 is connected via a suitable hydraulic line to the outlet port of shuttle valve 12. Shuttle valvesll and 12 are typical shuttle valves. These shuttle valves are manufactured by Offshore Systems Inc. manufacturers of Payne Products. The shuttle valves may be of the standard type wherein a piston is moved as a function of the velocity of hydraulic fluid applied to either side thereof or a positive displacement type shuttle valve as described in the copending application of V. H. Payne entitled Pressure Operated-Positive Displacement Shuttle Valve and bearing Ser. No. 877,120.

Shuttle valves 11 and 12 each have one inlet port thereof connected to a separate outlet port of three position valve 13. Shuttle valves 11 and 12 furthermore each have one inlet port thereof connected to a separate outlet port of three position valve 14. Three position valves 13 and 14 are the valves which form the instant invention and are described in detail hereinafter.

Three position valve 13 has the inlet port connected to Input 1. The pilot-pressure inlet of three position valve 13 is connected to Regulator l. The operating pressure inlet of valve 13 is connected to Regulator 2 via normally open gate valve 16. The operating pressure inlet of valve 13 is further connected to Regulator 1 via normally closed gate valve 15.

The inlet port of three position valve 14 is connected to Input 2. Pilot pressure inlet of valve 14 is connected to Regulator 3. The operating pressure inlet of valve 14 is connected to Regulator 4 via normally open gate valve 18 and to Regulator 3 via normally closed gate valve 17. g

In operation, control signals are supplied to BOP 10 via valves 11 through 14 in accordance with conditions which are established at the surface control unit or console. For example, pressurized hydraulic fluid is supplied via any suitable known means to Inputs 1 and 2. The pressurized hydraulic fluid is supplied to the inlet ports of valves 13 and 14. In addition, Regulator 1 and Regulator 3 are designed to supply a standard reference or pilot pressure. In a preferred embodiment,

the reference or pilot pressure is on the order of 500 psi. This pressure is supplied to the pilot pressure inlet port of valves 13 and 14.

Similarly, Regulator 2 and Regulator 4 are designed to provide pressurized hydraulic fluid as well. In the case of Regulators 2 and 4, the hydraulic fluid is pres surized to 1,500 psi. The operating pressure represented by the 1,500 psi hydraulic fluid is selectively applied to the operating pressure inlet of valves 13 and 14 in accordance with the operating conditions of gate valves 16 and 18, respectively.

In a typical operation, gate valve 16 is open while gate valve 15 is closed. Thus, pilot pressure hydraulic fluid of 500 psi is applied to the pilot pressure inlet port of valve 13 by Regulator 1. Conversely, a 1,500 psi hydraulic fluid is applied to the operating pressure inlet of valve 13. The pressure differential operates on a piston (see FIG. 2) within valve 13 so that Input 1 is essentially connected to the input of shuttle valve 12 via valve 13. However, shuttle valve 11 will not receive a pressurized hydraulic fluid signal via valve 13. The hydraulic fluid which is supplied to shuttle valve 12 causes operation of valve 12 such that the hydraulic fluid is passed therethrough to BOP 10 to effect a suitable operation thereof. In this embodiment, the conditions described supra cause BOP 10 to open.

Meanwhile, since three position valve 13 and the associated control apparatus is operating properly, gate valve 18 is closed and gate valve 17 is open. Consequently, 500 psi hydraulic fluid is supplied to both the pilot pressure inlet and the operating pressure inlets of three position valve 14. As will be described hereinafter, the equal pressure on opposite sides of the piston in valve 14 causes this piston to assume a position wherein Input 2 is blocked relative to both of the outlets of valve 14. Consequently, no pressurized hydraulic fluid is supplied to either of valves 11 or 12 by valve 14.

If now the operation of BOP 10 is required, gate valve 16 is closed while gate 15 remains closed. Consequently, the 500 psi hydraulic fluid continues to be applied to the pilot pressure inlet of valve 13 while psi hydraulic fluid is supplied to the operating pressure inlet of valve 13. This pressure differential will operate upon the piston in valve 13 whereby Input 1 now communicates with the other outlet port thereof whereby hydraulic fluid is supplied to shuttle valve 11. Conversely, no pressurized hydraulic fluid is supplied to shuttle valve 12 via valve 13. Since valve 14 does not supply any pressurized hydraulic fluid to either of valves 11 or 12.as noted supra, shuttle valve 11 is now operated,

whereby hydraulic fluid passes therethrough to BOP 10. In this embodiment, the hydraulic fluid is supplied to BOP to effect pressure on piston 10A to effective ly close the BOP. This kind of operation wherein BOP 10 is opened or closed as a function of the pressures supplied to the operating pressure inlet of valve 13 will continue. That is, operation of gate valve 16 will permit selective operation of valve 13 which controls shuttle valves 11 and 12 and, thereby, the application of hydraulic fluid to BOP 10.

If now, a malfunction occurs relative to the controlling units whereby it becomes desirable to direct the operation of the system by the redundant controls, gate valve 16 is closed and gate valve is opened. Thus, a similar pressure is applied to the pilot pressure and operating pressure inlets of valve 13 whereby the valve blocks Input 1 from the outlets. Thus, Input 1 does not communicate with either of the outlets of valve 13 and shuttle valve 1 1 and 12 are not affected thereby.

contemporaneously therewith, gate valve 17 is closed and gate valve 18 is placed in the appropriate position. Thus, if gate valve 18 remains closed, the 500 psi hydraulic fluid pressure is applied to the pilot pressure inlet of valve 14 and causes valve 14 to assume one condition. Conversely, if gate valve 18 is opened, the

1,500 psi hydraulic fluid is applied to the operating pressure inlet of valve 14 and causes valve 14 to assume a different condition.

Depending upon the condition of valve 14 (as described above), Input 2 communicates with one of the outlets thereof. Thus, either shuttle valve 11 or shuttle valve 12 is caused to operate thereby providing communication from Input 2 through to BOP 10.

Thus, it is shown that two separate and redundant control systems can be used to control the operation of BOP 10.

Referring now to FIGS. 2 and 3 concurrently, there are shown sectional views of the valve which forms the instant invention. This valve is represented by valves 13 or 14 in FIG. 1 and a description of either valve applies to both. Valve 13 (FIG. 2) includes an outer housing having a body 50. Body 50 may be fabricated by any suitable technique as for example by machining barstock or it may be molded or the like. Typically, body 50 has a substantially rectangular configuration. That is, body 50 is an elongated member which has a substantially square end-view configuration. Bore 51 is provided in body 50 along the longitudinal axis thereof. Bore 51 may be provided by suitable machining or molding operations on body 50. Bore 51 extends through body 50 in the elongated dimension.

The housing also includes a pilot pressure end cap 52 for one end of body 50 and a pressure end cap 53 at the other end of body 50. Pilot pressure end cap 52 has an external configuration which substantially mates with the external configuration of body 50. End cap 52 is mounted on body 50 by means of the bolt and washer assembly 99. The internal configuration of end cap 52 includes a first reduced portion 52A which substantially mates with the inner surface of bore 51. An annular groove is supplied in the outer surface of reduced portion 52A of end cap 52 and O-ring 54 is inserted in .the annular groove. O-ring 54 provides a seal between end cap 52 and body 50.

A further reduced portion 52B of end cap 52 extends into bore 51 in body 50. A large axial bore or cavity 58 is provided-in the reduced portions of end cap 52. An annular groove is provided on the inner surface of cavity 58 and O-ring 55 is inserted into the groove. The pilot pressure inlet bore is provided in end cap 52 and communicates with cavity 58 so that hydraulic pressure from the pilot pressure regulator source can be supplied to the internal components of valve 13. A suitable threaded coupling may be provided at the pilot pressure bore whereby hydraulic lines may be coupled thereto.

End cap 53 also has an external configuration which is similar to the configuration of body 50. End cap 53 is mounted on housing 50 by means of the bolt and washer assemblies 98. In addition, end cap 53 includes a first reduced portion 53A which mates with the insidesurface of bore 51 in body 50. An annular groove is provided in reduced portion 53A and O'-ring 56 is inserted into this annular groove. O-ring 56 provides a seal between end cap 53 and body 50. A further reduced portion 53B of end cap 53 extends inwardly of bore 51 in body 50. Extended portion 538 has a large bore or cavity 57 therein. The relationship between cavity 57 and cavity 58 is a function of the relative pressures which will be applied at the pilot pressure inlet and the operating pressure inlet. The operating pressure inlet is provided in the external surface of end caps 53 and communicates with the operating pressure source to cavity 57.

Centering piston 59 is a cup-like sleeve member which is disposed within cavity 57. The outer diameter of centering piston 59 is substantially similar to the internal diameter of of cavity 57. An annular groove on the inner surface of cavity 57 is provided for O-ring 60 whereby a fluid seal is provided between the surface of cavity 57 in end cap 53 and the outer surface of centering piston 59.

Centering piston 59 includes a cavity 61 therein. Cavity 61 is in the nature of an axial bore which passes only. part way through the length of centering piston 59. Aperture 61A in the bottom of centering piston 59 provides communication between cavities 57 and 61. An annular groove provided in the inner surface of centering piston 59 retains O-ring 62. As will be described in detail, O-ring 62 provides a fluid seal with an arm of a shiftable inner body within the housing of valve 13. Centering piston retainer 63 is a substantially disk-like or washer-like retainer which is mounted at the end of reduced portion 53B of end cap 53 by means of suitable screws 64. Centering piston retainer 63 includes a center aperture therein through which the operating piston arm passes. Retainer 63 retains centering piston 59 within cavity 57. As is seen, centering-piston 59 is shorter than the depth dimension of cavity 57 whereby centering piston 59 is free to move longitudinally within cavity 57.

An aperture is provided in the upper surface of body 50. This aperture passes through the external portion of the body and communicates with bore 51 in body 50. Inlet seal plate 64 is mounted in the aperture. Seal plate 64 may be of a substantially cylindrical configuration, having dimensions which are similar to the dimensions of the aforementioned aperture. Bore 65 passes through seal plate 64 and communicates with internal bore 51. An annular groove is provided around the circumference of seal plate 64 to retain O-ring 66 to provide a hydraulic seal between seal plate 64 and body 50. Inlet flange 67 is fabricated of any suitable barstock or the like and is mounted on the exterior of body 50 adjacent seal plate 64. Inlet flange 67 has dimensions which are larger than the aperture for seal plate 64 and is, typically, rectangular in configuration. Inlet port 68 has a threaded portion for receiving suitable inlet fittings. Inlet port 68 communicates with bore 65 in inlet seal plate 64 to provide an inlet to bore 51. An annular groove surrounds the internal bore end of port 68 to retain O-ring 69. O-ring 69 provides a hydraulic seal between the surfaces of inlet flange 67 and seal plate 64 adjacent the juncture of bores 65 and 68. Inlet flange 67 is mounted on body 50 by means of suitable bolt and ring 73 provides a hydraulic seal between outlet seal plate 72 and body 50. Outlet seal plate 72 includes two bores which pass therethrough. In the embodiment disclosed, bores 74 and 75 have different configurations and dimensions at the internal and external surfaces thereof. However, with a relatively minor modification in the dimensions of seal plate 72, bores 74 and 75 need not have any unusual configuration. The important consideration is that the internal surface area of outlet seal plate 72 between bores 74 and 75 must be at least as large as the opening in the operating piston as will be described hereinafter.

Outlet flange 76 may be fabricated of barstock or the like and is mounted at the exterior of body by means of the bolt and washer assemblies 77. Two outlet bores 78 and 79 respectively are provided in outlet flange 76. Bores 78 and 79 may be drilled or molded in flange 76. Outlet bore 78 has a portion thereof which communicates with bore 74 in outlet seal plate 72 to provide one outlet from bore 51. Likewise, bore 79 has a portion thereof which communicates with bore 75 of outlet seal plate 72 to provide another outlet from bore 51. The external ends of bores 78 and 79 include suitable threaded coupling arrangements for connection to other hydraulic hardware. By suitable recess screw assemblies 80, outlet seal plate 72 is affixed to outlet flange 76. Annular grooves are provided in the internal surface of outlet flange 76 which grooves individually surround the bore portions which mate with bores 74 and 75. These annular grooves are utilized to retain 0- rings 81. O-rings 81 provide hydraulic seals between outlet seal plate 72 and outlet flange 76 with regard to the communication of the respective bores in the aforementioned elements.

Shiftable inner body 82 may be: fabricated of ordinary barstock. Body82 comprises enlarged center portion and two protruding pistons or arm portions which have different diameters. Enlarged center portion 84 is essentially cubic in configuration. Appropriate beveling at the corners of the cube is utilized to provide better operation and avoid edges which may bind in operation of the valve. Elongated arm 83 extends from one side of center portion 84. Arm 83' passes through the aperture in center piston retainer 63 and into cavity 61 in centering piston 59. Another arm 85 extends from the opposite side of enlarged center portion 84 into cavity 58 in end cap 52. Arm 85 has a diameter which is approximately twice the diameter of arm 83. Thus, the piston area upon which force is exerted by pressurized hydraulic fluid is much larger in the case of arm than inthe case ofarrn 83.

Bore 86 passes through enlarged portion 84 transverse to the center line of arms 83 and 85. A pair of shear seals or rings 87 and 88 are mounted in aperture 86. Coil spring 89 is mounted in bore 86 between shear seals 87 and 88 causing the shear seals to be forced outwardly and into contact with inlet seal plate 64 and outlet seal plate 72, respectively. O-rings 90 and 91 are retained in suitable annular grooves of the circumference of seals 87 and 88, respectively. O-rings 90 and 91 provide hydraulic seals between the shear seals and the internal surface of bore 86.

Referring specifically to FIG. 3, a return flange 97 is mounted on body 50 by means of suitable bolt and washer assemblies 93. Return flange 97 may be fabricated of any suitable barstock or the like. Central bore 94 passes through return flange 92. Bore 94 may include suitable coupling or threaded portions for connection with other hardware. For example, check valve may be inserted. However, the coupling may be excluded entirely. An annular groove surrounds bore 94 on the inner surface of return flange 92 and retains O- ring 95. O-ring 95 provides a hydraulic seal between the surfaces of return flange 92 and body 50. Bore 94 communicates with bore 96 which passes through the side of body 50.

In operation, inlet port 68 is connected to a suitable input device. The input device supplies hydraulic fluid to the valve under suitable pressure. Outlets 1 and 2 are connected to a suitable utilization device as for example the shuttle valve as shown in FIG. 1. Pilot pressure inlet port is connected to a regulator for receiving a reference pressure signal in the form of a hydraulic fluid. The operating pressure inlet is connected to a source of hydraulic fluid which supplies fluid having a selectively variable pressure.

The object of the operation of the valve is to selectively transfer the hydraulic fluid supplied at the inlet to one of the outlets via the apertured inner body 82. In the alternative, the inlet is isolated from either of the outlets with a suitable positioning of inner body 82.

As suggested supra, the pilot pressure is arbitrarily designated as 500 psi. The operating pressure varies between and 1,500 psi. With valve 13 in the position shown in FIG. 2, the conditions exist wherein the 500 psi pilot pressure is applied to the pilot pressure inlet while the l,500 psi hydraulic fluid is supplied to the operating pressure inlet. Thus, the 1,500 psi hydraulic fluid pressure signal is supplied to the end surface of centering piston 59 to force the piston to the leftmost position as shown. In addition, the operating pressure hydraulic fluid is supplied against the endmost surface of arm 83 via aperture 61A in centering piston 59. The application of 1,500 psi hydraulic fluid on the surface area at the end of arm 83 is sufficient to overcome the total force exerted by the 500 psi pilot pressure on the end surface of arm 85.

In this position, hydraulic fluid supplied at inlet port 68 passes through port 68 and port 65 in the inlet seal plate. Fluid further passes through the aperture in seal ring 88, aperture 86 in inner body. 82, the aperture in seal ring 87 and communicates with bore 74 in outlet seal plate 72; Since bore 74 communicates with bore 78 associated with outlet 1, fluid also flows through this path. Thus, with a 1,500 psi hydraulic fluid signal supplied to the operating pressure inlet, the hydraulic fluid supplied at inlet port 68 communicates with outlet 1 and is supplied to a suitable utilization device.

If now, by controlling the surface units, the operating pressure is diminished to 500 psi (i.e. identical to the pilot pressure signal or within a suitable range thereof) inner body 82 will be moved toward the right in FIG. 2. That is, the 500 psi hydraulic fluid signal as applied against the end surface of arm 83 is insufficient to overcome the 500 psi force applied against the end surface of arm 85. However, as inner body 82 slides toward the right, the end surface of arm 83 abuts against the bottom of cavity 61 in centering piston 59. Thus, cavity 61 is effectively eliminated. The 500 psi force applied against the end of arm 85 tends to continue pushing piston 82 toward the right. However, the 500 psihydraulic fluid force applied at the operating pressure inlet port now abuts against the effective end surface of centering piston 57 inasmuch as port 61A is effectively closed by the end surface of arm 83. Thus, enlarged portion 84 of inner body 82 shifts only a distance equivalent to the distance between the end surface of arm 83 and the bottom surface of the cavity 61. This distance has been predetermined to be sufficient to cause the aperture in seal ring 87 to be disengaged from each of bores 74 and 75. Thus, seal ring 87 abuts against the polished surface of outlet seal plate 72 effecting a good seal therebetween. Since fluid flowing through aperture 86 cannot communicate with bores 74 and 75, the inlet hydraulic fluid is essentially blocked.

If now, the operating pressure supplied to the operat ing pressure inlet port is reduced to 0 psi, the 500 psi pilot pressure fluid acts upon the end surface of arm 85 of inner body 82 and forces inner body 82 to the rightmost position. That is, the end surface of arm 83 bears against the inner surface of bore 61 of centering piston 59. The continued pressure on the end surface of arm 85 causes inner body 82 to move toward the right such that arm 83 moves centering piston 59 along therewith until the end surface of centering piston 59 abuts against the bottom surface of cavity 57. When inner body 82 has moved to the rightmost position described, aperture 86 and the apertures in the respective shear seals 88 and 87 communicate from inlet port 68 to outlet port 79 via port in outlet seal plate 72.

Thus, it has been shown that hydraulic fluids supplied at the inlet can be controllably supplied to either of the outlets or to neither of the outlets depending upon the hydraulic fluid pressure supplied at the operating pressure inlet. Clearly, the same operation would occur if the operating pressure dropped from 1,500 psi to 0 psi without the intermediate step. In that instance, inner body 82 would move smoothly and continuously from the leftmost position to the rightmost position without stopping in a centering or blocking step. However, because of the relative dimensions of the aperture in inner body 82 and the space provided between bores 74 and 75 there would be no spurious and undesirable interconnection between inlet source and both outlets. In other words, only one outlet can ever be connected to the inlet at a given time. Consequently, ambiguities in operation are eliminated.

Furthermore, if the operating pressure fluid changes from 0 psi to 500 psi or 1,500 psi inner body 82 will move from the rightmost position to the blocked position (or leftmost position) in the reverse manner to that described. However, the same advantages obtained. That is, the outlet ports are never simultaneously communicating with the inlet port. In addition, the outlet ports can never communicate one-with-the-other to ef fect an improper and undesirable operation of a utilization device connected to one or the other of the outlets.

In addition, when inner body 82 is moved in valve 13, one or more of outlet ports 74 or 75 no longer communicate with bore 86 in inner body 82. The bore (or bores) which do not communicate with bore 86 obviously communicate with the interior cavity 51 of valve 13. Since the fluid which is returned to valve 13 from the system is under pressure, it must be discharged in order to prevent valve 13 from becoming pressure locked. Consequently, the fluid which is discharged into cavity 51 is discharged from the valve via ports 96 and 94. In subsea units, the fluid may be discharged to the sea. In land units, the discharge fluid may be returned to a suitable accumulator or the like.

Thus, there is described a preferred embodiment of the instant invention. Those skilled in the art may be able to conceive modifications to this valve. However, any modifications which fall within the purview of the invention are intended to be included therein. The specific configuration and/or dimensions which are recited herein are meant to be illustrative only and are not limitative. For example, the various ports may be located on different sides of the valve and the relative placement thereof may vary somewhat. These and other modifications which may beutilized by those skilled in the art and which fall within the inventive precepts hereinabove noted, are meant to be included withinthis description.

Having thus described the preferred embodiment of the invention, the embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A valve, comprising a housing having a bore therein intermediate its opposite ends, a body shiftable within the bore between a first position near one end, a

second position near the other end, and a position intermediate the first and second positions, said housing having an inlet to and a pair of outlets from the bore, said body having port means connecting the inlet with one of the outlets in its first position, connecting the inlet with the other outlet in its second position, and disconnecting the inlet from both outlets in its intermediate position, means for urging the body from its first to its second position, means in the bodyproviding a cavity connecting with the bore, a sleeve sealably reciprocable within the cavity, a piston on the inner body sealably reciprocable within the sleeve, a port in the body connecting with the cavity for admitting fluid pressure thereto for urging said piston and said sleeve in a direction to move the body to its first position, means on the sleeve engageable by the piston, as the piston moves in the opposite direction, to cause the sleeve to follow the piston as the body moves from its intermediate to its second position, and means on the cavity engageable 'with the sleeve, as the sleeve moves in said first-mentioned direction, to prevent movement of the sleeve with the piston as the body moves from its intermediate to its first position.

2. A valve of the character defined in claim 1,

providing another cavity connecting with the bore, a piston on the inner body sealably reciprocable in said other cavity, and a port in the body connecting with said other cavity for admitting fluid pressure thereto to ends, the inner diameter of the ring adjacent the outlets being less than the longitudinal distance between the outlets so as to prevent communication with both when said body is in its intermediate position.

r wherein the urging means comprises means in the body 4. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device, including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second source, comprising: a body member having a longitudinally extending bore therein between a pilot end andan operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, and a second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture, said plate having a bore extending therethrough in fluid communication with said longitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore extending therethrough from the inner surface to the outer surface of said plate; a pilot pressure end cap mounted at the pilot end of said body member, said cap having a bore therein communicating with the longitudinal bore in said body member; an operating pressure end cap mounted at the operating end of said body member, said cap having a bore therein communicating with the longitudinal bore in said body member; an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position, and a second end position near the operating end of said body memben said inner body. having a central portion with a bore extending traversely therethrough and first and second arm portionsextending longitudinally from said central portion and slidable respectively within'the bores in the pilot pressure cap and operating pressure cap, seal means positioned at each end of the bore in the central portion of said inner body, said seal means being adapted I to prevent fluid communication with said bore in the central portion of the inner body other than through said bore in the input seal plate and through said first and second bores in said output seal plate, and spring means positioned in said bore in the central portion of the piston means and adapted to maintain said seal means in contact with the inner surfaces of the output and the input seal plates, said bore in the central portionbeing in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the outlet plate is provided when said inner body is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner body is at its second end position, and fluid communication between the bore in the central portion and said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position, whereby the fluid operating pressure introduced. to the valve at the operating end of said body member and the fluid pilot pressure in troduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of end positions and, if desired, to its intermediate position.

5. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device, including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second source, comprising: a body member having a longitudinally extending bore therein between a pilot end and an operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, and a second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture, said plate having a bore extending therethrough in fluid communication with said longitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore ex-.

tending therethrough from the inner surface to the outer surface of said plate; a pilot pressure end cap mounted at the pilot end of said body member, an operating pressure end cap mounted at the operating end of said body member, an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position, and a second end position near the operating end of said body member, said inner body having a central portion with a bore extending traversely therethrough and first and second arm portions extending longitudinally from said central portion, said pilot pressure end cap and said operating pressure end cap each have a portion extending into the interior of said body member, said extended portion of the pilot end cap having a cavity therein adapted to receive the first arm portion of the inner body extending toward the pilot end of the body member, said extended portion of the operating end cap having a cavity therein adapted to receive the second arm portion of the inner body extending toward the operating end of the body member, said bore in the central portion being in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the outlet plate is provided when said inner body is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner body is at its second end position, and fluid communication between the bore in the central portion and said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position, whereby the fluid operating pressure introduced to the valve at the operating end of said body member and the fluid pilot pressure introduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of its end positions and, if desired, to its intermediate position.

6. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device,

including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second source, comprising: a body member having a longitudinally extending bore therein between a pilot end and an operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, and a second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture, said plate having a bore extending therethrough in fluid communication with said longitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore extending therethrough from the inner surface to the outer surface of said plate; a pilot pressure end cap mounted at the pilot end of said body member, said cap having a cavity therein communicating with the longitudinal bore in said body member; an operating pressure end cap mounted at the operating end of said body member, said cap having a cavity therein communicating with the longitudinal bore in said body member; an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position, and a second end position near the operating end of said body member, said inner body having a central portion with a bore extending traversely therethrough and first and second arm portions extending longitudinally from said central portion, said first arm portion being slidable within the cavity in the pilot pressure cap, a centering piston member slidable in the cavity of said operating pressure end cap, said centering piston member having a cavity therein adapted to slidably receive said second arm portion of the inner body and being shorter than the depth dimension of the cavity in the operating end cap, whereby said centering piston member can move longitudinally within the cavity in said operating end cap, said bore in the central portion being in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the out let plate is provided when said inner body is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner body is at its second end position, and fluid communication between the bore in the central portion and said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position; whereby the fluid operating pressure introduced to the valve at the operating end of said body member and the fluid pilot pressure introduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of its end positions and, if desired, to its intermediate position.

7. The valve of claim 6, said first arm portion of the piston means is larger than the cross-sectional area of the second arm portion of said piston means.

8. The valve of claim 6 in which said cavity in the centering piston member extends only part way through the length of said member from the end thereof toward the center of the body member toward the operating end thereof, said cavity being in fluid communication with the bore in said operating end cap through a bore in the end of said centering piston member.

9. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device, including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second source, comprising: a body member having a longitudinally extending bore therein between a pilot end and an operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, anda second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture,

said plate having a bore extending therethrough in fluid communication with said longitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore extending therethrough from the inner surface to the I bore in fluid communication with said first bore in the outlet plate and a second outlet bore in fluid communioperating pressure end cap mounted at the operating end of said body member, said cap having a bore therein communicating with the longitudinal bore in said body member; an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position,and a second end position near the operating end of said body member, said inner body having a central portion with a bore extending traversely therethrough and first and second arm portions extending longitudinally from said central portion and slidable respectively within the bores in the pilot pressure cap and operating pressure cap, said bore in the central portion being in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the outlet plate is provided when said inner body-is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner ho is at its secon end osition an fluid co unicat i n between the bore 11? the ceritr portion an said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position, whereby the fluid operating pressure introduced to the valve at the operating end of said body member and the fluid pilot pressure introduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of its end positions and, if desired, to its intermediate position. 

1. A valve, comprising a housing having a bore therein intermediate its opposite ends, a body shiftable within the bore between a first position near one end, a second position near the other end, and a position intermediate the first and second positions, said housing having an inlet to and a pair of outlets from the bore, said body having port means connecting the inlet with one of the outlets in its first position, connecting the inlet with the other outlet in its second position, and disconnecting the inlet from both outlets in its intermediate position, means for urging the body from its first to its second position, means in the body providing a cavity connecting with the bore, a sleeve sealably reciprocable within the cavity, a piston on the inner body sealably reciprocable within the sleeve, a port in the body connecting with the cavity for admitting fluid pressure thereto for urging said piston and said sleeve in a direction to move the body to its first position, means on the sleeve engageable by the piston, as the piston moves in the opposite direction, to cause the sleeve to follow the piston as the body moves from its intermediate to its second position, and means on the cavity engageable with the sleeve, as the sleeve moves in said first-mentioned direction, to prevent movement of the sleeve with the piston as the body moves from its intermediate to its first position.
 2. A valve of the character defined in claim 1, wherein the urging means comprises means in the body providing another cavity connecting with the bore, a piston on the inner body sealably reciprocable in said other cavity, and a port in the body connecting with said other cavity for admitting fluid pressure thereto to urge said piston and said sleeve in a direction to move the body to its second position.
 3. A valve of the character defined in claim 1, wherein said port means comprises a single port having seal rings therein urged outwardly toward each of its ends, the inner diameter of the ring adjacent the outlets being less than the longitudinal distance between the outlets so as to prevent communication with both when said body is in its intermediate position.
 4. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device, including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second sourcE, comprising: a body member having a longitudinally extending bore therein between a pilot end and an operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, and a second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture, said plate having a bore extending therethrough in fluid communication with said longitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore extending therethrough from the inner surface to the outer surface of said plate; a pilot pressure end cap mounted at the pilot end of said body member, said cap having a bore therein communicating with the longitudinal bore in said body member; an operating pressure end cap mounted at the operating end of said body member, said cap having a bore therein communicating with the longitudinal bore in said body member; an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position, and a second end position near the operating end of said body member, said inner body having a central portion with a bore extending traversely therethrough and first and second arm portions extending longitudinally from said central portion and slidable respectively within the bores in the pilot pressure cap and operating pressure cap, seal means positioned at each end of the bore in the central portion of said inner body, said seal means being adapted to prevent fluid communication with said bore in the central portion of the inner body other than through said bore in the input seal plate and through said first and second bores in said output seal plate, and spring means positioned in said bore in the central portion of the piston means and adapted to maintain said seal means in contact with the inner surfaces of the output and the input seal plates, said bore in the central portion being in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the outlet plate is provided when said inner body is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner body is at its second end position, and fluid communication between the bore in the central portion and said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position, whereby the fluid operating pressure introduced to the valve at the operating end of said body member and the fluid pilot pressure introduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of its end positions and, if desired, to its intermediate position.
 5. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device, including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second source, comprising: a body member having a longitudinally extending bore therein between a pilot end and an operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, and a second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture, said plate having a bore extending therethrough in fluid communication with said lOngitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore extending therethrough from the inner surface to the outer surface of said plate; a pilot pressure end cap mounted at the pilot end of said body member, an operating pressure end cap mounted at the operating end of said body member, an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position, and a second end position near the operating end of said body member, said inner body having a central portion with a bore extending traversely therethrough and first and second arm portions extending longitudinally from said central portion, said pilot pressure end cap and said operating pressure end cap each have a portion extending into the interior of said body member, said extended portion of the pilot end cap having a cavity therein adapted to receive the first arm portion of the inner body extending toward the pilot end of the body member, said extended portion of the operating end cap having a cavity therein adapted to receive the second arm portion of the inner body extending toward the operating end of the body member, said bore in the central portion being in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the outlet plate is provided when said inner body is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner body is at its second end position, and fluid communication between the bore in the central portion and said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position, whereby the fluid operating pressure introduced to the valve at the operating end of said body member and the fluid pilot pressure introduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of its end positions and, if desired, to its intermediate position.
 6. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device, including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second source, comprising: a body member having a longitudinally extending bore therein between a pilot end and an operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, and a second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture, said plate having a bore extending therethrough in fluid communication with said longitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore extending therethrough from the inner surface to the outer surface of said plate; a pilot pressure end cap mounted at the pilot end of said body member, said cap having a cavity therein communicating with the longitudinal bore in said body member; an operating pressure end cap mounted at the operating end of said body member, said cap having a cavity therein communicating with the longitudinal bore in said body member; an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position, and a second end position near the operating end of Said body member, said inner body having a central portion with a bore extending traversely therethrough and first and second arm portions extending longitudinally from said central portion, said first arm portion being slidable within the cavity in the pilot pressure cap, a centering piston member slidable in the cavity of said operating pressure end cap, said centering piston member having a cavity therein adapted to slidably receive said second arm portion of the inner body and being shorter than the depth dimension of the cavity in the operating end cap, whereby said centering piston member can move longitudinally within the cavity in said operating end cap, said bore in the central portion being in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the outlet plate is provided when said inner body is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner body is at its second end position, and fluid communication between the bore in the central portion and said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position; whereby the fluid operating pressure introduced to the valve at the operating end of said body member and the fluid pilot pressure introduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of its end positions and, if desired, to its intermediate position.
 7. The valve of claim 6, said first arm portion of the piston means is larger than the cross-sectional area of the second arm portion of said piston means.
 8. The valve of claim 6 in which said cavity in the centering piston member extends only part way through the length of said member from the end thereof toward the center of the body member toward the operating end thereof, said cavity being in fluid communication with the bore in said operating end cap through a bore in the end of said centering piston member.
 9. A three-position valve adapted to control the flow of fluid to a fluid pressure-operated utilization device, including selectively passing said fluid through either of two outlet lines to said device, and blocking the flow through both of said outlet lines, in response to the relationship between a fluid operating pressure applied from one source and a pilot pressure applied from a second source, comprising: a body member having a longitudinally extending bore therein between a pilot end and an operating end, and having a first aperture extending through the upper portion of said body member and communicating with said bore, and a second aperture extending through the bottom portion of said body member and communicating with said bore; an inlet seal plate positioned in said first aperture, said plate having a bore extending therethrough in fluid communication with said longitudinal bore in the body member; an outlet seal plate positioned in said second aperture, said plate having a first and a second bore extending therethrough from the inner surface to the outer surface of said plate; including an inlet flange mounted on the external surface of the body member, said inlet flange supporting the inlet seal plate and having an inlet port in fluid communication with the bore in the inlet seal plate, an outlet flange mounted on the exterior of said body member, said outlet flange supporting the outlet seal plate and having a first outlet bore in fluid communication with said first bore in the outlet plate and a second outlet bore in fluid communication with said second bore in the outlet plate, a pilot pressure end cap mounted at the pilot end of said body member, said cap having a bore therein communicating with the longitudinal bore in said body membeR; an operating pressure end cap mounted at the operating end of said body member, said cap having a bore therein communicating with the longitudinal bore in said body member; an inner body positioned in the bore in said body member and adapted for movement therein between a first end position near the pilot end of said body member, an intermediate position, and a second end position near the operating end of said body member, said inner body having a central portion with a bore extending traversely therethrough and first and second arm portions extending longitudinally from said central portion and slidable respectively within the bores in the pilot pressure cap and operating pressure cap, said bore in the central portion being in fluid communication with the bore in the inlet seal plate, the size of said bore in the central portion being such, in relationship to the distance between the first and second bores in the outlet seal plate, that fluid communication between the bore in the central portion and the first bore in the outlet plate is provided when said inner body is at its first end position, fluid communication between the bore in the central portion and said second bore in the outlet plate is provided when said inner body is at its second end position, and fluid communication between the bore in the central portion and said first and second bores in the outlet plate is blocked when said inner body is positioned at said intermediate position; whereby the fluid operating pressure introduced to the valve at the operating end of said body member and the fluid pilot pressure introduced thereto at the pilot end of the body member can be regulated so that said inner body is forced to one of its end positions and, if desired, to its intermediate position. 